U.S. patent number 8,864,933 [Application Number 12/908,698] was granted by the patent office on 2014-10-21 for substrate treatment apparatus and substrate treatment method.
This patent grant is currently assigned to Tokyo Electron Limited. The grantee listed for this patent is Tsuyoshi Mizuno, Shouichi Terada, Takeshi Uehara. Invention is credited to Tsuyoshi Mizuno, Shouichi Terada, Takeshi Uehara.
United States Patent |
8,864,933 |
Terada , et al. |
October 21, 2014 |
**Please see images for:
( Certificate of Correction ) ** |
Substrate treatment apparatus and substrate treatment method
Abstract
In a substrate treatment method for supplying a coating solution
to a substrate with projections and depressions on a front surface
thereof to form a coating film on the front surface of the
substrate, the coating solution is supplied to the rotating
substrate to form a coating film on the front surface of the
substrate, and the substrate having the coating film formed thereon
is heated to adjust an etching condition of the coating film. Next,
the etching solution is supplied to the rotating substrate to etch
the coating film, and thereafter the coating solution is supplied
to the substrate to form a flat coating film on the front surface
of the substrate. Thereafter, the substrate is heated to cure the
coating film. This flattens the coating film with uniformity and
high accuracy without undergoing a high-load process such as
chemical mechanical polishing.
Inventors: |
Terada; Shouichi (Koshi,
JP), Mizuno; Tsuyoshi (Koshi, JP), Uehara;
Takeshi (Koshi, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
Terada; Shouichi
Mizuno; Tsuyoshi
Uehara; Takeshi |
Koshi
Koshi
Koshi |
N/A
N/A
N/A |
JP
JP
JP |
|
|
Assignee: |
Tokyo Electron Limited (Tokyo,
JP)
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Family
ID: |
37491981 |
Appl.
No.: |
12/908,698 |
Filed: |
October 20, 2010 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20110030897 A1 |
Feb 10, 2011 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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11562909 |
Nov 22, 2006 |
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61830120 |
Jul 12, 2006 |
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Foreign Application Priority Data
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Nov 24, 2005 [JP] |
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2005-338114 |
Jul 4, 2006 [JP] |
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2006-183981 |
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Current U.S.
Class: |
156/345.27;
156/345.21; 118/719; 156/345.52; 118/720; 118/715; 156/345.24 |
Current CPC
Class: |
H01L
21/02282 (20130101); H01L 21/6715 (20130101); H01L
21/31055 (20130101); H01L 21/316 (20130101); H01L
21/31111 (20130101) |
Current International
Class: |
C23F
1/08 (20060101) |
Field of
Search: |
;156/345.55,345.21,345.16,345.24,345.27,345.52,345.53
;118/715,719,720 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1267904 |
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Sep 2000 |
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CN |
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1343326 |
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Apr 2002 |
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CN |
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1674232 |
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Sep 2005 |
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CN |
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06-097068 |
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Apr 1994 |
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JP |
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07-047324 |
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Feb 1995 |
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JP |
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08-306877 |
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Nov 1996 |
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JP |
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11-329938 |
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Nov 1999 |
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JP |
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2002-026016 |
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Jan 2002 |
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JP |
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396509 |
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Jul 2000 |
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TW |
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416120 |
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Dec 2000 |
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TW |
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489358 |
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Jun 2002 |
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TW |
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Other References
Office Action issued May 17, 2010, in Taiwan Patent Application No.
095143596. cited by applicant .
Office Action issued Sep. 23, 2010, in Taiwan Patent Application
No. 095143596. cited by applicant .
Office Action issued Jun. 27, 2008, in China Patent Application No.
200610163747.4 (with English translation). cited by
applicant.
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Primary Examiner: MacArthur; Sylvia R
Attorney, Agent or Firm: Oblon, Spivak, McClelland, Maier
& Neustadt, L.L.P.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a divisional of U.S. Ser. No. 11/562,909, filed
Nov. 22, 2006, the entire contents of which is incorporated herein
by reference. U.S. Ser. No. 11/562,909 claims the benefit of
priority under 35 U.S.C. .sctn.119(e) of U.S. Provisional
Application No. 60/830,120, filed Jul. 12, 2006, and claims the
benefit of priority under 35 U.S.C. .sctn.119 from Japanese Patent
Application Nos. 2005-338114, filed on Nov. 24, 2005 and
2006-183981, filed on Jul. 4, 2006.
Claims
What is claimed is:
1. A substrate treatment apparatus for supplying a coating solution
to a substrate with projections and depressions on a front surface
thereof to form a coating film on the front surface of the
substrate, comprising: a cassette station which stores a plurality
of substrates; and a processing station which receives said
substrates from the cassette station disposed outside the
processing station, said processing station including, a coating
unit including, a holder which holds respective ones of the
substrates to be horizontally rotatable, a coating solution supply
nozzle configured to supply the coating solution, a glass-forming
compound to the substrate held by said holding means, an etching
solution supply nozzle configured to supply an etching solution for
etching the coating film formed on the substrate held by holder, a
heater which heats the substrate, and a temperature adjusting
device which adjusts the temperature of said heater, a buffer unit
disposed inside the processing station, separate from the cassette
station, separate from the coating unit, and temporarily holds the
substrate inside the processing station, a transfer device within
the processing station configured to transfer the substrate
directly from the coating unit to the buffer unit, and a controller
configured to provide rotation control of said holder, supply
control of said coating solution supply nozzle and etching solution
supply nozzle, and temperature control of said temperature
adjusting means, wherein said controller comprises a processor
programmed to provide control signals to the coating unit and the
buffer unit which execute a first coating step of supplying the
coating solution including the glass-forming compound to the
substrate rotated by said holder to form a first spin on glass
coating film on the front surface of the substrate, thereafter a
step of heating the substrate having the first spin on glass
coating film formed thereon to adjust an etching condition of the
first spin on glass coating film, a step of supplying the etching
solution to the substrate to etch the first spin on glass coating
film, thereafter a second coating step of supplying the coating
solution including the glass-forming compound to the substrate to
form a flat second spin on glass coating film on the front surface
of the substrate, and then a step of heating the substrate to cure
the second spin on glass coating film, and wherein the controller
is programmed to provide control signals to provide control signals
to the coating unit and the buffer unit which control an order of
processing such that, when said first coating step, said first
heating step, said etching step, said second coating step, and said
second heating step are repeatedly performed, a plurality of the
substrates for which treatments for a first time have been finished
are temporarily housed in the buffer unit in sequence, and after
said first coating step for a last substrate in a lot is finished,
treatments for a second time for the substrates are sequentially
carried out.
2. The substrate treatment apparatus as set forth in claim 1,
wherein said heater is embedded in said holder.
3. The substrate treatment apparatus as set forth in claim 1,
further comprising: a cooling device which cools the substrate.
4. The substrate treatment apparatus as set forth in claim 1,
wherein the etching solution is one of a solvent for the coating
solution, a hydrofluoric acid solution, an acid solution and an
alkaline solution.
5. The substrate treatment apparatus as set forth in claim 1,
wherein the etching solution supply nozzle and the coating solution
supply nozzle are attached together and moveable as a unit.
6. The substrate treatment apparatus as set forth in claim 1,
wherein said controller adjust a heating time during the step of
heating to adjust the etching conditions of the coating film.
7. A substrate treatment apparatus for supplying a coating solution
to a substrate with projections and depressions on a front surface
thereof to form a coating film on the front surface of the
substrate, comprising: a coating unit which forms the coating film
on the front surface of the substrate; an etching unit which etches
the coating film formed on the substrate; a heating unit having a
heating unit which heats the substrate; a temperature adjusting
unit which adjusts the temperature of said heating means; a cooling
unit having a cooling unit which cools the substrate; a buffer unit
which holds and processes the substrate; a carrier unit configured
to carry the substrate directly between the buffer unit and one of
said coating unit, etching unit, heating unit, and cooling unit;
and a control unit configured to control said coating, etching and
heating units, said temperature adjusting unit, and said buffer
unit, wherein said coating unit comprises a holding mechanism which
holds the substrate to be horizontally rotatable, and a coating
solution supply nozzle which supplies, for the coating solution, a
glass-forming compound to the substrate held by said holding
mechanism, wherein said etching unit comprises a holding mechanism
which holds the substrate to be horizontally rotatable, and an
etching solution supply nozzle which supplies an etching solution
for etching the coating film formed on the substrate, wherein said
control unit comprises a processor programmed to provide control
signals which execute a step of supplying the coating solution
including the glass-forming compound to the substrate rotated by
said holding means of said coating unit to form a first spin on
glass coating film on the front surface of the substrate, a step of
heating the substrate having the first spin on glass coating film
formed thereon to adjust an etching condition of the first spin on
glass coating film, a step of supplying the etching solution to the
substrate to etch the first spin on glass coating film, a
subsequent step of supplying the coating solution including the
glass-forming compound to the substrate to form a flat second spin
on glass coating film on the front surface of the substrate, and
then a step of heating the substrate to cure the second spin on
glass coating film, and wherein the control unit is programmed to
provide control signals to provide control signals to the coating
unit and the buffer unit which control an order of processing such
that, when said first coating step, said first heating step, said
etching step, said second coating step, and said second heating
step are repeatedly performed, a plurality of the substrates for
which treatments for a first time have been finished are
temporarily housed in the buffer unit in sequence, and after said
first coating step for a last substrate in a lot is finished,
treatments for a second time for the substrates are sequentially
carried out.
8. The substrate treatment apparatus as set forth in claim 7,
wherein said etching unit has a cleaning solution supply nozzle for
supplying a cleaning solution for suppressing etching to the
substrate.
9. The substrate treatment apparatus as set forth in claim 7,
wherein said etching unit has a drying gas supply nozzle for
supplying a drying gas to the substrate.
10. The substrate treatment apparatus as set forth in claim 7,
wherein said etching unit is composed of a plurality of units
capable of supplying different kinds of etching solutions different
from each other so that the etching unit selected according to a
condition of the film thickness or the like of the coating film is
usable.
11. The substrate treatment apparatus as set forth in claim 7,
wherein said etching unit has a temperature adjusting means for
adjusting the temperature of the etching solution to a
predetermined temperature, said temperature adjusting means being
provided along a supply pipe connecting an etching solution supply
source and said etching solution supply nozzle.
12. The substrate treatment apparatus as set forth in claim 7,
wherein said etching unit has a concentration adjusting means for
adjusting the concentration of the etching solution to a
predetermined concentration.
13. The substrate treatment apparatus as set forth in claim 7,
wherein said coating unit has an etching solution supply nozzle for
supplying an etching solution for etching the coating film formed
on the substrate.
14. The substrate treatment apparatus as set forth in claim 7,
wherein the etching solution supply nozzle and the coating solution
supply nozzle are attached together and moveable as a unit.
15. The substrate treatment apparatus as set forth in claim 7,
wherein said control unit is programmed to provide control signals
which adjust a heating time during the step of heating to adjust
the etching conditions of the coating film.
16. A substrate treatment apparatus for supplying a coating
solution to a substrate with projections and depressions on a front
surface thereof to form a coating film on the front surface of the
substrate, comprising: a holder which holds the substrate to be
horizontally rotatable; a coating solution supply nozzle configured
to supply the coating solution, a glass-forming compound to the
substrate held by said holder; an etching solution supply nozzle
configured to supply an etching solution for etching the coating
film formed on the substrate held by said holder; a heater which
heats the substrate; a temperature adjusting device which adjusts
the temperature of said heater; and a controller configured to
provide rotation control of said holder, supply control of said
coating solution supply nozzle and etching solution supply nozzle,
and temperature control of said temperature adjusting device,
wherein said controller comprises a processor programmed to provide
control signals which execute a step of supplying the coating
solution including the glass-forming compound to the substrate
rotated by said holder to form a first spin on glass coating film
on the front surface of the substrate, thereafter a step of heating
the substrate having the first spin on glass coating film formed
thereon to adjust an etching condition of the coating film, a step
of supplying the etching solution to the substrate to etch the
first spin on glass coating film, thereafter a subsequent step of
supplying the coating solution including the glass-forming compound
to the substrate to form a flat second spin on glass coating film
on the front surface of the substrate, and then a step of heating
the substrate to cure the second spin on glass coating film, and
wherein said controller is configured to adjust a heating time
during the step of heating to adjust the etching conditions of the
first spin on glass coating film.
17. A substrate treatment apparatus for supplying a coating
solution to a substrate with projections and depressions on a front
surface thereof to form a coating film on the front surface of the
substrate, comprising: a coating unit configured to form the
coating film on the front surface of the substrate; an etching unit
configured to etch the coating film formed on the substrate; a
heating unit having a heating unit which heats the substrate; a
temperature adjusting unit which adjusts the temperature of said
heating means; a cooling unit having a cooling unit which cools the
substrate; a carrier unit which carries in/out the substrate
between said coating unit, etching unit, heating unit, and cooling
unit; and a control unit configured to control said coating,
etching and heating units and said temperature adjusting unit,
wherein said coating unit comprises a holding mechanism which holds
the substrate to be horizontally rotatable, and a coating solution
supply nozzle which supplies, for the coating solution, a
glass-forming compound to the substrate held by said holding
mechanism, wherein said etching unit comprises a holding mechanism
which holds the substrate to be horizontally rotatable, and an
etching solution supply nozzle which supplies an etching solution
for etching the coating film formed on the substrate, wherein said
control unit comprises a processor programmed to provide control
signals which execute a step of supplying the coating solution
including the glass-forming compound to the substrate rotated by
said holding means of said coating unit to form a first spin on
glass coating film on the front surface of the substrate, a step of
heating the substrate having the first spin on glass coating film
formed thereon to adjust an etching condition of the first spin on
glass coating film, a step of supplying the etching solution to the
substrate to etch the first spin on glass coating film, a
subsequent step of supplying the coating solution including the
glass-forming compound to the substrate to form a flat second spin
on glass coating film on the front surface of the substrate, and
then a step of heating the substrate to cure the second spin on
glass coating film, and wherein said control unit is programmed to
provide control signals which adjust a heating time during the step
of heating to adjust the etching conditions of the first spin on
glass coating film.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a substrate treatment method and a
substrate treatment apparatus and, more specifically, to a
substrate treatment method of applying a coating solution to a
substrate, for example, a semiconductor wafer, an LCD substrate and
the like to form a coating film on the front surface of the
substrate and an apparatus therefor.
2. Description of the Related Art
Conventionally, a technology of forming multilayer wiring on the
substrate is employed with an increase in integration of
semiconductor devices, in which a silicon oxide film-based glass
that is referred to as SOG (Spin On Glass) is used as a film for
insulating wirings in the multilayer wiring, that is, circuit
patterns from each other.
The method of forming the SOG film is generally a method of
applying a glass component molten in an organic solvent onto the
substrate by a spin-coat method, and drying and burning it by
thermal treatment such as baking or curing to bond the glass
component thereto, thus forming a film.
However, a circuit pattern with projections and depressions is
formed on the front surface of the substrate, and therefore when a
typical spin coating method and thermal drying are performed,
unevenness in shape of the film surface following the shape of
level differences of the projections and depressions occurs,
causing problems in subsequent process steps. The problems are, for
example, that for lithography, if performed, various poor
conditions are caused, such as degradation in line width (CD) due
to an increased focal depth, an increase in level difference with
stacking of films and so on.
Hence, there is a need to flatten the coating film. As the method
of flattening the coating film, a chemical mechanical polishing
(CMP) technology is known in which after the coating film is cured
by thermal treatment, a polishing solution containing mechanical
polishing particles and chemical polishing particles is then
dropped onto the surface of a polishing cloth being a polishing
member, and the surface of the polishing cloth is pressed against
the coating film on the substrate to remove a part of the coating
film.
Besides, as another flattening method without undergoing the
high-load process such as CMP, a coating method and apparatus are
known in which a coating solution is supplied to the substrate
surface having an uneven surface so that a coating film is spread
out to be thin over the surface of the substrate by a scanner
plate, and an air pressure from a nozzle in a slit form is used to
evenly press it (see Claims and FIG. 1, FIG. 2, and FIG. 4 in
Japanese Patent Application Laid-open No. Hei 7-47324). As still
another means, a coating method and apparatus are known in which a
coating solution is supplied to the surface of the substrate, a gas
containing a solvent vapor is then supplied to thereby make the
coating film thin and even (see paragraph number 0142 and FIG. 8
and FIG. 13 in Japanese Patent Application Laid-open No. Hei
11-329938).
SUMMARY OF THE INVENTION
However, the technology described in Japanese Patent Application
Laid-open No. Hei 7-47324 has a problem. The problem is that since
air is blown to the coating solution, the coating solution
evaporates to harden, resulting in a decrease in flowability to
fail to sufficiently uniformize the coating film.
In the technology described in Japanese Patent Application
Laid-open No. Hei 11-329938, evaporation of the coating solution
can be suppressed more as compared to the former technology since
the solvent vapor is sent to the coating solution, but the coating
solution evaporates to harden as in the former technology due to
influence of the surrounding environment in the treatment section,
resulting in a decrease in flowability. Accordingly, this
technology also has a problem of the coating film being not
sufficiently uniformized.
The present invention has been developed in consideration of the
above circumstances, and its object is to flatten the coating film
with uniformity and high accuracy without undergoing a high-load
process such as CMP.
In order to attain the above object, the present invention
includes: a first coating step of supplying a coating solution to
the substrate with projections and depressions on the front surface
thereof to form a coating film on the front surface of the
substrate; a first drying step of heating the substrate having the
coating film formed thereon to adjust an etching condition of the
coating film; an etching step of supplying an etching solution for
etching the coating film formed on the substrate to etch the
coating film; a second coating step of supplying the coating
solution to the substrate to form a flat coating film on the front
surface of the substrate; and after the second coating step, a
second drying step of heating the substrate to cure the coating
film.
According to the present invention, it is possible that after the
coating film is formed on the front surface of the substrate with
projections and depressions on the front surface, the substrate is
heated to adjust the etching conditions of the coating film, such
as the etching amount, the etching time, and so on, the etching
solution is used to etch the coating film in the etching step so as
to remove the excessive film, thereafter the coating solution is
supplied again onto the etched coating film to form a flat coating
film, and the substrate is heated to cure (bake) the coating
film.
After the second drying step, the second coating step and second
drying step are repeatedly performed, thereby making it possible to
stack the cured coating films one on the other and to further
decrease the level difference on the front surface of the coating
film. In such a viewpoint, the first coating step, first drying
step, etching step, second coating step, and second drying step may
be repeatedly performed.
After each of the first drying step and second drying step, a
cooling step of cooling the substrate may be provided. This can
rapidly lower the temperature of the substrate which has been at a
high temperature in the first drying step and second drying step to
an optimum temperature for the etching step being a subsequent
step.
In the substrate treatment method, when the first coating step,
first drying step, etching step, second coating step, and second
drying step are repeatedly performed, a plurality of the substrates
for which treatments for the first time have been finished may be
temporarily housed in a buffer unit in sequence, and after the
first coating step for the last substrate in a lot is finished,
treatments for the second time for the substrates sequentially
carried out of the buffer unit may be started.
In the first and second coating steps, the coating solution may be
supplied to the front surface of the substrate with the substrate
being horizontally rotated, and in the etching step, the etching
solution may be supplied to the front surface of the substrate with
the substrate being horizontally rotated. This makes it possible to
uniformly form the coating film on the entire front surface of the
substrate in the first coating step, to etch the coating film
uniformly in the horizontal direction and in the depth direction in
the etching step, and to uniformly form the coating film on the
front surface of the etched coating film in the second coating
step.
In the first drying step and second drying step, the substrate may
be horizontally rotated, and a drying gas may be supplied to the
substrate. This allows a centrifugal force caused by the rotation
of the substrate to remove the etching solution served for the
treatment and the supply of the drying gas to dry the
substrate.
In the present invention, the temperature of the etching solution
is preferably adjusted, for example, to 20.degree. C. to 50.degree.
C. Further, as the etching solution, one of a solvent for the
coating solution, a hydrofluoric acid solution, an acid solution
and an alkaline solution can be used.
According to another aspect, a substrate treatment apparatus of the
present invention includes: a holding means for holding the
substrate to be horizontally rotatable; a coating solution supply
nozzle for supplying the coating solution to the substrate held by
the holding means; an etching solution supply nozzle for supplying
an etching solution for etching the coating film formed on the
substrate held by the holding means; a heating means for heating
the substrate; a temperature adjusting means for adjusting the
temperature of the heating means; and a control means for
conducting rotation control of the holding means, supply control of
the coating solution supply nozzle and etching solution supply
nozzle, and temperature control of the temperature adjusting means.
The control means executes a step of supplying the coating solution
to the substrate rotated by the holding means to form a coating
film on the front surface of the substrate, thereafter a step of
heating the substrate having the coating film formed thereon to
adjust an etching condition of the coating film, a step of
supplying the etching solution to the substrate to etch the coating
film, thereafter a step of supplying the coating solution to the
substrate to form a flat coating film on the front surface of the
substrate, and then a step of heating the substrate to cure the
coating film. In this case, the heating means may be embedded in
the holding means. The substrate treatment apparatus may further
include a cooling means for cooling the substrate.
According to still another aspect, the substrate treatment
apparatus of the present invention is a substrate treatment
apparatus for supplying a coating solution to a substrate with
projections and depressions on a front surface thereof to form a
coating film on the front surface of the substrate, including: a
coating unit for forming the coating film on the front surface of
the substrate; an etching unit for etching the coating film formed
on the substrate; a heating unit having a heating means for heating
the substrate; a temperature adjusting means for adjusting the
temperature of the heating means; a cooling unit having a cooling
means for cooling the substrate; a carrier unit for carrying-in/out
the substrate between the coating unit, etching unit, heating unit,
and cooling unit; and a control means for controlling the units and
the temperature adjusting means. The coating unit includes a
holding means for holding the substrate to be horizontally
rotatable and a coating solution supply nozzle for supplying the
coating solution to the substrate held by the holding means, and
the etching unit includes a holding means for holding the substrate
to be horizontally rotatable and an etching solution supply nozzle
for supplying an etching solution for etching the coating film
formed on the substrate. The control means executes a step of
supplying the coating solution to the substrate rotated by the
holding means of the coating unit to form a coating film on the
front surface of the substrate, a step of heating the substrate
having the coating film formed thereon to adjust an etching
condition of the coating film, a step of supplying the etching
solution to the substrate to etch the coating film, a step of
supplying the coating solution to the substrate to form a flat
coating film on the front surface of the substrate, and then a step
of heating the substrate to cure the coating film.
In this case, the etching unit may further have a cleaning solution
supply nozzle for supplying a cleaning solution for suppressing
etching to the substrate. Further, the coating unit has an etching
solution supply nozzle for supplying an etching solution for
etching the coating film formed on the substrate.
The substrate treatment apparatus may further include a buffer unit
to/from which the carrier unit is capable of delivering and
receiving the substrate, and which is capable of housing a
plurality of the substrates. Further, in the substrate treatment
apparatus, the etching unit may have a drying gas supply nozzle for
supplying a drying gas to the substrate.
Further, in the substrate treatment apparatus, the etching unit may
be composed of a plurality of units capable of supplying different
kinds of etching solutions different from each other so that the
etching unit selected according to a condition of the film
thickness or the like of the coating film is usable. This makes it
possible to etch the coating film using a most suitable etching
solution for the condition of the film thickness or the like of the
coating film.
Further, in the substrate treatment apparatus, the etching unit may
have a temperature adjusting means for adjusting the temperature of
the etching solution to a predetermined temperature, the
temperature adjusting means being provided along a supply pipe
connecting an etching solution supply source and the etching
solution supply nozzle.
Further, the etching unit may include a concentration adjusting
means for adjusting the concentration of the etching solution to a
predetermined concentration. As the etching solution, for example,
one of a solvent for the coating solution, a hydrofluoric acid
solution, an acid solution and an alkaline solution can be
used.
As described above, according to the present invention, the coating
film can be formed with its initial level difference due to
projections and repressions being made small within an allowable
range, so that the coating film can be flattened with uniformity
and high accuracy.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic side view showing a first embodiment of a
substrate treatment apparatus according to the present
invention;
FIG. 2A to FIG. 2C are enlarged cross-sectional views of a main
part each showing a film formation state of a coating film in the
first embodiment of a substrate treatment method according to the
present invention;
FIG. 3A to FIG. 3F are schematic perspective views each showing
each step in the present invention;
FIG. 4 is a flowchart showing a procedure of film formation of a
coating film in the first embodiment of the substrate treatment
method according to the present invention;
FIG. 5 is a graph showing the relation between the etching amount
of a solvent and the heating time in the present invention;
FIG. 6 is a flowchart showing a procedure of film formation of the
coating film in a second embodiment of the substrate treatment
method according to the present invention;
FIG. 7A to FIG. 7D are enlarged cross-sectional views of a main
part each showing a film formation state of the coating film in the
second embodiment of the substrate treatment method according to
the present invention;
FIG. 8 is a flowchart showing a procedure of film formation of the
coating film in a third embodiment of the substrate treatment
method according to the present invention;
FIG. 9A to FIG. 9F are enlarged cross-sectional views of a main
part each showing a film formation state of the coating film in the
third embodiment of the substrate treatment method according to the
present invention;
FIG. 10 is a schematic cross-sectional view showing a second
embodiment of the substrate treatment apparatus according to the
present invention;
FIG. 11A to FIG. 11E are schematic perspective views each showing
each step when the substrate treatment apparatus shown in FIG. 10
is used;
FIG. 12A is a schematic plan view showing an example of a substrate
processing system including the substrate treatment apparatus
according to the present invention, FIG. 12B is a schematic side
view showing a first unit group in the substrate processing system,
and FIG. 12C is a schematic side view showing a second unit
group;
FIG. 13 is a schematic cross-sectional view showing an example of
an etching unit in the present invention;
FIG. 14 is a flowchart showing a procedure of film formation of the
coating film in a fourth embodiment of the substrate treatment
method according to the present invention; and
FIG. 15 is a flowchart showing a procedure of film formation of the
coating film in a fifth embodiment of the substrate treatment
method according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Hereinafter, preferred embodiments of the present invention will be
described in detail with reference to the accompanying drawings. A
case will be described now in which the substrate treatment method
according to the present invention is applied to the SOG film
forming method for a semiconductor wafer.
FIG. 1 is a schematic cross-sectional view showing a first
embodiment of a substrate treatment apparatus according to the
present invention. The substrate treatment apparatus includes a
spin chuck 10 that is a rotating and holding means for holding and
horizontally rotating a semiconductor wafer W (hereinafter,
referred to as a wafer W) that is a substrate having an uneven
surface, a heating means 20 for heating the wafer W to a
predetermined temperature, a cooling means 22 for cooling the wafer
W heated by the heating means 20, a coating solution supply nozzle
30 for dropping (supplying) an SOG solution, such as polysilazane
that is a coating solution onto the front surface of the wafer W,
and a solvent supply nozzle 40 for dropping (supplying) a solvent
for the coating solution (SOG) as an etching solution, such as
dibutyl ether onto the front surface of the wafer W.
The spin chuck 10 is housed in a cup 50 composed of an outer cup 51
capable of rising and lowering and an inner cup 52, and coupled to
a motor 12 via a rotation axis 11 passing through a bottom portion
53 of the inner cup 52 in a manner to be able to rise and lower.
The motor 12 rotates at a predetermined number of rotations based
on a control signal from a controller 60 constituted by a control
means, for example, a central processing unit (CPU). The spin chuck
10 is also configured to be able to rise and lower by means of a
not-shown raising and lowering means. The spin chuck 10 is
configured to receive the wafer W from a carrier arm (not shown)
being a carrier unit moved to a position above the spin chuck 10,
which is movable in a horizontal X-Y direction and a vertical
Z-direction and horizontally rotatable, hold the wafer W thereon by
suction, and pass the wafer W to the carrier arm raised and moved
to the position above the spin chuck 10 after a later-described
treatment for a coating film is finished. Note that the carrier arm
is controlled by the controller 60.
The heating means 20 is composed of a hot plate incorporating a
heater 20a disposed in a heating unit 200 located outside a coating
unit 100 in which the spin chuck 10 and the cup 50 are disposed,
and connected to a temperature adjuster 21 that is a temperature
adjusting means. The heating means 20 is configured to be set a
predetermined temperature, that is, a temperature to adjust etching
conditions, for example, 150.degree. C. and a temperature to cure
(bake) the coating film, for example, 160.degree. C. by the
temperature adjuster 21 being controlled based on the control
signal from the controller 60.
In this case, the etching conditions can be appropriately selected
from the relation between the etching amount and heating time
(etching time). For example, when the solvent (dibutyl ether) for
the coating solution (SOG) was discharged (dropped, supplied) to a
central position of the wafer W for 10 seconds at 1 cc/sec, and the
relation between the etching amount (nm) and the heating time (sec)
under a condition of a heating temperature of 150.degree. C. was
evaluated, the result shown in FIG. 5 was obtained. As can be seen
from the evaluation result, if the heating time is long, etching no
longer proceeds, whereas if the heating time is short, complete
peeling occurs. The heating time is selected based on the
evaluation result. For example, when a heating time of 120 (sec) is
selected, the etching amount is 120 (nm), whereas when a heating
time of 210 (sec) is selected, the etching amount is about 50
(nm).
The control of the etching amount can be conducted by the heating
conditions such as the heating temperature, the heating time and so
on, by the solvent conditions of the discharge amount (the drop
amount, the supply amount), the discharge time and so on of the
solvent, or by a combination of both the heating conditions and the
solvent conditions.
The cooling means 22 is composed of a cooling plate incorporating a
coolant pipe 22a disposed in a cooling unit 300 located under the
heating unit 200, and connected to a cooling temperature adjuster
23 that is a cooling temperature adjusting means. The cooling means
22 is set to lower the temperature of the wafer W heated by the
heating means 20 to a predetermined temperature, for example,
23.degree. C. by the cooling temperature adjuster 23 being
controlled based on the control signal from the controller 60. Note
that the cooling means 22 may be provided beside the heating means
20.
A carry-in/out port 400 for the wafer W is provided at the side of
each of the coating unit 100, the heating unit 200 and the cooling
unit 300, and can be opened/closed by a shutter 500 which is raised
and lowered by a not-shown raising and lowering mechanism. Further,
a not-shown carrier arm controlled by the controller 60 can deliver
the wafer W between the coating unit 100, the heating unit 200 and
the cooling unit 300.
On the other hand, the coating solution supply nozzle 30 is
connected to a coating solution supply source 32 via a coating
solution supply pipe 31 provided with an open/close valve V1.
Besides, the solvent supply nozzle 40 is disposed adjacent to the
coating solution supply nozzle 30 and connected to a solvent supply
source 42 via a solvent solution supply pipe 41 provided with an
open/close valve V2. Note that a temperature adjuster 80 that is a
temperature adjusting means for adjusting the temperature of the
coating solution and the solvent to a predetermined temperature,
for example, 20.degree. C. to 50.degree. C. is provided along the
coating solution supply pipe 31 and the solvent supply pipe 41. The
coating solution supply nozzle 30 and the solvent supply nozzle 40
are formed to be able to move, by means of a nozzle moving
mechanism 70, to a position above a central position of the spin
chuck 10 and to a waiting position outside the cup 50. In this
case, the nozzle moving mechanism 70 moves the coating solution
supply nozzle 30 and the solvent supply nozzle 40 to the position
above the central position of the spin chuck 10 and to the waiting
position outside the cup 50 based on the control signal from the
controller 60.
Next, the operational aspect of the substrate treatment apparatus
according to the present invention configured as described above
will be described with reference to FIG. 1, FIGS. 2A to 2C, FIGS.
3A to 3F, and the flowchart shown in FIG. 4.
First of all, an unprocessed wafer W is carried into the coating
unit 100 and delivered to the spin chuck 10 by the not-shown
carrier arm. The carrier arm then retracts, and the outer cup 51
rises. In this state, the open/close valve V1 provided along the
coating solution supply pipe 31 is opened based on the control
signal from the controller 60, and the motor 12 of the spin chuck
10 is driven. This allows the coating solution to be dropped
(supplied) from the coating solution supply nozzle 30 onto the
front surface of the wafer W rotating with the rotation of the spin
chuck 10 as shown in FIG. 3A to form a coating film T of the
coating solution with a level difference H on the front surface of
the wafer W (see FIG. 2A) {first coating step: step S4-1}. After
the formation of the coating film, the open/close valve V1 is
closed based on the control signal from the controller 60 and the
motor 12 is stopped.
Next, the carrier arm receives the wafer W on the spin chuck 10 and
delivers the wafer W onto the hot plate 20 being the heating means
in the heating unit 200. Based on the control signal from the
controller 60, the temperature adjuster 21 operates to raise the
temperature of the heater 20a of the heating means 20 to, for
example, 150.degree. C. to heat the wafer W for a heating time
selected in advance from FIG. 5 to adjust the etching condition.
This evaporates a part of liquid in the coating film T to slightly
decrease the level difference in the coating film T as shown in
FIG. 3B {first drying step: step S4-2}.
Next, the carrier arm receives the wafer W on the hot plate 20 and
delivers the wafer W onto the cooling plate 22 being the cooling
means in the cooling unit 300. Based on the control signal from the
controller 60, the cooling temperature adjuster 23 operates to set
the temperature of the coolant of the cooling means 22 to, for
example, 23.degree. C. to lower the temperature of the wafer W to
23.degree. C. as shown in FIG. 3C {cooling step: step S4-3}.
Next, the carrier arm receives the wafer W on the cooling plate 22
and delivers the wafer W to the spin chuck 10 in the coating unit
100. Based on the control signal from the controller 60, the
solvent supply nozzle 40 then moves to a position above the central
portion of the wafer W, the open/close valve V2 provided along the
solvent supply pipe 41 is opened, and the motor 12 of the spin
chuck 10 is driven. This allows the solvent to be dropped
(supplied) from the solvent supply nozzle 40 onto the front surface
of the wafer W rotating with the rotation of the spin chuck 10 as
shown in FIG. 3D to isotropically etch the coating film T (see FIG.
2B) {etching step: step S4-4}. After the isotropic etching with the
solvent, the solvent (etching solution) is shaken out.
After the etching treatment, based on the control signal from the
controller 60, the open/close valve V2 is closed, while the coating
solution supply nozzle 30 moves again to the position above the
central portion of the wafer W. In this state, the open/close valve
V1 is opened based on the control signal from the controller 60,
the coating solution is dropped (supplied) from the coating
solution supply nozzle 30 onto the front surface of the wafer W
rotating with the rotation of the spin chuck 10 as shown in FIG. 3E
to form a substantially flat coating film T with a small level
difference h within an allowable range on the front surface of the
wafer W (see FIG. 2C) {second coating step: step S4-5}.
After the coating film is formed as described above, based on the
control signal from the controller 60, the open/close valve V1 is
closed, and the motor 12 is stopped. The carrier arm then receives
the wafer W on the spin chuck 10 and delivers the wafer W onto the
hot plate 20 (heating means) in the heating unit 200. Based on the
control signal from the controller 60, the temperature adjuster 21
operates to raise the temperature of the heater 20a to, for
example, 160.degree. C. to heat the wafer W to thereby cure (bake)
the coating film as shown in FIG. 3F {second drying step: step
S4-6}.
After the curing (baking) treatment of the coating film T is
performed as described above, the outer cup 51 is lowered and the
spin chuck 10 is raised to pass the wafer W to the carrier arm
which moves to the position above the spin chuck 10, so that the
wafer W is carried out by the carrier arm from the substrate
treatment apparatus.
While a case in which a flat coating film is formed on the front
surface of the wafer W with projections and depressions through the
first coating step, the first drying step, the cooling step, the
etching step, the second coating step, and the second drying step
has been described in the above embodiment, the second coating step
and the second drying step may be repeatedly performed in order to
further decrease the level difference in the coating film T. More
specifically, as shown in FIG. 6, the first coating step (step
S6-1), the first drying step (step S6-2), the first cooling step
(step S6-3), the etching step (step S6-4), the second coating step
(step S6-5), the second drying step (step S6-6), and the second
cooling step (step S6-7) are performed as in the first embodiment
to form a coating film T with a level difference h smaller than the
level difference H in the initial coating film T, as shown in FIG.
7C, and thereafter the second coating step for the second time
(step S6-8) and the second drying step for the second time (step
S6-9) may be performed. This ensures that the coating films T are
stacked and a coating film T with a level difference h0 smaller
than the level difference h is formed.
In place of the second embodiment, the first coating step, the
first drying step, the first cooling step, the etching step, the
second coating step, the second drying step, and the second cooling
step may be repeatedly performed a plurality of times. For example,
as shown in FIG. 8, the first coating step (step S8-1, see FIG.
9A), the first drying step (step S8-2), the first cooling step
(step S8-3), the etching step (step S8-4, see FIG. 9B), the second
coating step (step S8-5), the second drying step (step S8-6), and
the second cooling step (step S8-7) are performed as in the first
embodiment to form a coating film T with a level difference h1
smaller than the level difference H in the initial coating film T,
as shown in FIG. 9C, and thereafter the first coating step for the
second time (step S8-8) may be performed to form a coating film T
with a level difference h2 smaller than the level difference h1
(see FIG. 9D), and then the first drying step for the second time
(step S8-9), the first cooling step for the second time (step
S8-10), the etching step for the second time (step S8-11, see FIG.
9E), the second coating step for the second time (step S8-12), and
the second drying step for the second time (step S8-13) may be
performed. This ensures that the coating films T are stacked and a
coating film T with a level difference h3 further smaller than the
level difference h2 is formed (see FIG. 9F).
Note that while a case in which the heating means 20 is disposed in
the heating unit 200 outside the coating unit 100 has been
described in the above-described embodiments, the heating means may
be composed of a heater 20a embedded in the spin chuck 10 as shown
in FIG. 10. Note that in FIG. 10, other portions are the same as
those shown in FIG. 1, and therefore the same numbers are given to
those same portions to omit their description.
According to the substrate treatment apparatus configured as
described above, a coating film can be formed on the wafer W as
follows.
Namely, as shown in FIG. 11, an unprocessed wafer W is carried into
the cup 50 and delivered to the spin chuck 10 by a not-shown
carrier arm. The carrier arm then retracts, and the outer cup 50
rises. In this state, the open/close valve V1 provided along the
coating solution supply pipe 31 is opened based on the control
signal from the controller 60, and the motor 12 of the spin chuck
10 is driven. This allows the coating solution to be dropped
(supplied) from the coating solution supply nozzle 30 onto the
front surface of the wafer W rotating with the rotation of the spin
chuck 10 as shown in FIG. 11A to form a coating film T of the
coating solution with a level difference H on the front surface of
the wafer W (see FIG. 2A) {first coating step}.
After the formation of the coating film, the open/close valve V1 is
closed based on the control signal from the controller 60 and the
motor 12 is stopped. Next, based on the control signal from the
controller 60, the temperature adjuster 21 operates to raise the
temperature of the heater 20a being a heating means to, for
example, 150.degree. C. to heat the wafer W for a heating time
selected in advance from FIG. 5 to adjust the etching condition.
This evaporates a part of liquid in the coating film T to slightly
decrease the level difference in the coating film T as shown in
FIG. 11B {first drying step}. After the first drying step, the
wafer W is cooled to, for example, 23.degree. C. {first cooling
step}.
Based on the control signal from the controller 60, the solvent
supply nozzle 40 then moves to a position above the central portion
of the wafer W, the open/close valve V2 provided along the solvent
supply pipe 41 is opened, and the motor 12 of the spin chuck 10 is
driven. This allows the solvent to be dropped (supplied) from the
solvent supply nozzle 40 onto the front surface of the wafer W
rotating with the rotation of the spin chuck 10 as shown in FIG.
11C to isotropically etch the coating film T (see FIG. 2B) {etching
step}.
After the etching treatment, based on the control signal from the
controller 60, the open/close valve V2 is closed, while the coating
solution supply nozzle 30 moves again to the position above the
central portion of the wafer W. In this state, the open/close valve
V1 is opened based on the control signal from the controller 60,
the coating solution is dropped (supplied) from the coating
solution supply nozzle 30 onto the front surface of the wafer W
rotating with the rotation of the spin chuck 10 as shown in FIG.
11D to form a substantially flat coating film T with a small level
difference h within an allowable range on the front surface of the
wafer W (see FIG. 2C) {second coating step}.
After the coating film is formed as described above, based on the
control signal from the controller 60, the open/close valve V1 is
closed, and the motor 12 is stopped. Based on the control signal
from the controller 60, the temperature adjuster 21 then operates
to raise the temperature of the heater 20a to, for example,
160.degree. C. to heat the wafer W to thereby cure (bake) the
coating film as shown in FIG. 11E {second drying step}.
After the curing (baking) treatment of the coating film T is
performed as described above, the outer cup 51 is lowered and the
spin chuck 10 is raised to pass the wafer W to the carrier arm
which moves to the position above the spin chuck 10, so that the
wafer W is carried out by the carrier arm from the substrate
treatment apparatus.
While a case in which a flat coating film is formed on the front
surface of the wafer W with projections and depressions through the
first coating step, the first drying step, the first cooling step,
the etching step, the second coating step, and the second drying
step has been described in the above embodiment, the second coating
step and the second drying step may be repeatedly performed in
order to further decrease the level difference in the coating film
T as in the above description. Alternatively, the first coating
step, the first drying step, the first cooling step, the etching
step, the second coating step, the second drying step, and the
second cooling step may be repeatedly performed a plurality of
times.
While a case in which the etching solution for etching the coating
film is a solvent for SOG, such as dibutyl ether has been
described, etching solutions other than the solvent for SOG, for
example, a hydrofluoric acid solution such as HF, BHF or the like,
an acid solution such as hydrochloric acid, sulfuric acid or the
like, or an alkaline solution such as NaOH, KOH or the like can be
used depending on the conditions of the film thickness and so on of
SOG in the present invention.
Next, an example of a substrate processing system employing a
substrate treatment apparatus capable of treatment using different
etching solutions will be described.
The primary part of the substrate processing system is composed of,
as shown in FIG. 12A, a cassette station 1 which functions as a
carry-in portion and a carry-out portion for carrying-in/out a
plurality of, for example, 25 wafers W per wafer cassette C as a
unit from/to the outside to/from the system and carrying-in/out the
wafers W from/to the wafer cassette C; a processing station 2 for
performing formation of a coating film T, etching treatment and the
like on the wafer W; and an interface station 3 provided between
the cassette station 1 and the processing station 2 for
transferring the wafer W.
The interface station 3 is configured such that, as shown in FIG.
12A, a plurality of, for example, up to four wafer cassettes C are
mounted on a cassette mounting table 1a in a line along a
horizontal X-direction with the respective wafer ports facing
toward the processing station 2, and a pair of tweezers 4 for wafer
carriage, which is movable in a cassette-arrangement direction (an
X-direction) and in a wafer-arrangement direction of the wafers W
housed in the wafer cassette C (a Z-direction), performs selective
carriage for each of the wafer cassettes. The pair of tweezers 4
for wafer carriage is configured to be rotatable in a
.theta.-direction and can deliver the wafer W to a later-described
transfer unit (TRS1, TRS2) included in a multi-tired unit section
in a first unit group G1 on the processing station 2 side.
The processing station 2 comprises, as shown in FIG. 12A, two
coating units 100A and 100B each for forming a coating film of SOG
on the wafer W, three etching units composed of a hydrofluoric acid
solution etching unit 600A, an acid solution etching unit 600B, and
an alkaline solution etching unit 600C, the first unit group G1
disposed on the interface station 3 side in the processing station
2, a second unit group G2 disposed almost at central portion in the
processing station 2, a first carrier arm 5A disposed between the
coating units 100A and 100B, the first unit group G1, the second
unit group G2, and a later-described buffer unit 700 to deliver the
wafer W between the coating units 100A and 100B, the first unit
group G1, the second unit group G2, and the buffer unit 700, and a
second carrier unit 5B disposed between the second unit group G2,
the hydrofluoric acid solution etching unit 600A, the acid solution
etching unit 600B, and the alkaline solution etching unit 600C to
deliver the wafer W between the second unit group G2, the
hydrofluoric acid solution etching unit 600A, the acid solution
etching unit 600B, and the alkaline solution etching unit 600C.
Note that the buffer unit 700 is formed to be able to house a
plurality of wafers W therein.
In the first unit group G1, as shown in FIG. 12B, a first to a
fourth heating unit (HP1 to HP4), the first and second transfer
units (TRS1, TRS2), and a first and a second cooling unit (COL1,
COL2) are stacked in order from the upper side to the lower
side.
In the second unit group G2, as shown in FIG. 12C, a fifth to a
seventh heating unit (HP5 to HP7), a third and a fourth transfer
unit (TRS3, TRS4), and a third and a fourth cooling unit (COL3,
COL4) are stacked in order from the upper side to the lower
side.
In the substrate processing system configured as described above,
the first and second coating units 100A and 100B are configured
similarly to the coating unit 100 in the first embodiment, and
therefore their description will be omitted here. Further, the
first to seventh heating units HP1 to HP7 and the first to fourth
cooling units COL1 to COL 4 are also configured similarly to the
heating unit 200 and the cooling unit 300 in the first embodiment,
respectively.
On the other hand, the hydrofluoric acid solution etching unit
600A, the acid solution etching unit 600B, and the alkaline
solution etching unit 600C are similarly configured except that
those etching solutions are different from each other. Hereinafter,
the hydrofluoric acid solution etching unit 600A will be described
as a representative.
The hydrofluoric acid solution etching unit 600A comprises, as
shown in FIG. 13, a spin chuck 10A that is a rotating and holding
means for holding and horizontally rotating the wafer W, an etching
solution supply nozzle 6 for dropping (supplying) a hydrofluoric
acid solution that is the etching solution onto the front surface
of the wafer W, a cleaning solution supply nozzle 7 for supplying a
cleaning solution for suppressing (stopping) the etching, for
example, pure water onto the wafer W, and a drying gas supply
nozzle 8 for supplying (jetting) a drying gas, for example, a
nitrogen (N.sub.2) gas or clean air to the wafer W.
The spin chuck 10A is housed in a cup 50A composed of an outer cup
51A capable of rising and lowering and an inner cup 52A, and
coupled to a motor 12A via a rotation axis 11A passing through a
bottom portion 53A of the inner cup 52A in a manner to be able to
rise and lower. The motor 12A rotates at a predetermined number of
rotations based on a control signal from a controller 60A that is a
control means. The spin chuck 10A is also configured to be able to
rise and lower by means of a not-shown raising and lowering means.
The spin chuck 10A is configured to receive the wafer W from the
first carrier arm 5A being a carrier unit moved to a position above
the spin chuck 10A, which is movable in a horizontal X-Y direction
and a vertical Z-direction and horizontally rotatable, hold the
wafer W thereon by suction, and pass the wafer W to the first
carrier arm 5A raised and moved to the position above the spin
chuck 10A after a later-described coating film treatment is
finished. Note that the first carrier arm 5A and the second carrier
arm 5B are controlled by the controller 60A.
The etching supply nozzle 6 is connected via an etching solution
supply pipe 6a to a hydrofluoric acid solution tank 6b storing an
etching solution (hydrofluoric acid solution) that is the etching
solution supply source. The cleaning solution supply nozzle 7 is
connected via a pure water supply pipe 7a to a pure water tank 7b
storing pure water that is a cleaning solution supply source used
also for a diluted hydrofluoric acid solution. In this case, the
etching solution supply pipe 6a is provided with a pump P1, a flow
rate control valve FV1, and a switching valve CV from the
hydrofluoric acid solution tank 6b side. Further, the pure water
supply pipe 7a is provided with a pump P2 and a flow rate control
valve FV2 from the pure water tank 7b side, and a branch pipe 7c
branching from the secondary side of the flow rate control valve
FV2 is connected to the switching valve CV. The flow rate control
valve FV1, the flow rate control valve FV2 and the switching valve
CV constitute a concentration adjusting means 90 for the
hydrofluoric acid solution. More specifically, the flow rate
control valve FV1, the flow rate control valve FV2 and the
switching valve CV are controlled by the controller 60A so that
based on the control signal previously stored in the controller
60A, the hydrofluoric acid solution adjusted by the flow rate
control valve FV1 and the pure water adjusted by the flow rate
control valve FV2 can be mixed to obtain a hydrofluoric acid
solution with a predetermined concentration.
The etching solution supply pipe 6a is provided with a temperature
adjuster 80 that is a temperature control means for adjusting the
temperature of the etching solution to a predetermined temperature,
for example, 20.degree. C. to 50.degree. C. The temperature
adjuster 80 is controlled by the control signal from the controller
60A to adjust the temperature of the etching solution to a
predetermined temperature, for example, 20.degree. C. to 50.degree.
C. depending on the conditions of the film thickness and so on of
the coating film T.
The drying gas supply nozzle 8 is connected via a drying gas supply
pipe 8a provided with an open/close valve V3 to a drying gas supply
source, for example, a N2 gas supply source 8b.
The etching solution supply nozzle 6 and the cleaning solution
supply nozzle 7 are configured to be able to move by means of a
nozzle moving mechanism 70A to a position above a central position
of the spin chuck 10A and to a waiting position outside the cup
50A. The drying gas supply nozzle 8 is also configured to be able
to move by means of a nozzle moving mechanism 70B to a position
above a central position of the spin chuck 10A and to a waiting
position outside the cup 50A. Note that the drying gas supply
nozzle 8 is preferably inclined to supply (jet) the N2 gas from the
center of the wafer toward the peripheral side. Further, the drying
gas supply nozzle 8 preferably supplies (jets) the N2 gas while
scanning from a position above the center of the wafer W to a
position above the periphery. In this case, the nozzle moving
mechanisms 70A and 70B move the etching solution supply nozzle 6
and the cleaning solution supply nozzle 7, and the drying gas
supply nozzle 8 to the position above the central position of the
spin chuck 10A and to the waiting positions outside the cup 50A
based on the control signal from the controller 60A,
respectively.
Note that the acid solution etching unit 600B and the alkaline
solution etching unit 600C are configured similarly to the
hydrofluoric acid solution etching unit 600A except that those
etching solutions are different, that is, the etching solution tank
connected to the etching solution supply nozzle 6 is an acid
solution tank or an alkaline solution tank in replace of the
hydrofluoric acid solution tank 6b.
Next, a method of forming the coating film T in the substrate
processing system will be described with reference to FIGS. 2A to
2C, FIG. 5, and FIGS. 12A to 12C through FIG. 15.
<In the Case of Etching with the Solvent for the Coating
Film>
First of all, in the cassette station 1, the pair of tweezers 4 for
wafer carriage accesses the cassette C housing unprocessed wafers W
on the cassette mounting table 1a and takes out one wafer W from
the cassette C (step S14-1). After taking out the wafer W from the
cassette C, the pair of tweezers 4 for wafer carriage delivers the
wafer W to a mounting table (not shown) in the first transfer unit
TRS1 disposed in the first unit group G1 on the processing station
2 side (step S14-2). The first carrier arm 5A then receives the
wafer W from the first transfer unit TRS1 and delivers the wafer W
onto the cooling plate (not shown) in the first cooling unit COL1
disposed in the first unit group G1 to lower the temperature of the
wafer W to 23.degree. C. {pre-treatment cooling step: step
S14-3}.
The first carrier arm 5A then receives the wafer W on the cooling
plate in the first cooling unit COL1 and delivers the wafer W onto
the spin chuck 10 in the first coating unit 100A. Thereafter, the
coating solution is dropped (supplied) from the coating solution
supply nozzle 30 onto the front surface of the wafer W rotating
with the rotation of the spin chuck 10 as shown in FIG. 3A to form
a coating film T with a level difference H on the front surface of
the wafer W as in the first embodiment (see FIG. 2A) {first coating
step: step S14-4}.
The first carrier arm 5A then receives the wafer W on the spin
chuck 10 and delivers the wafer W onto the hot plate (not shown) in
the first or second heating unit HP1 or HP2 in the first unit group
G1. The wafer W is then heated for a heating time selected in
advance from FIG. 5 to adjust the etching condition. This
evaporates a part of liquid in the coating film T to slightly
decrease the level difference in the coating film T as shown in
FIG. 3B {first drying step: step S14-5}.
The first carrier arm 5A then receives the wafer W on the hot plate
in the first or second heating unit HP1 or HP2 and delivers the
wafer W onto the cooling plate in the first or second cooling unit
COL1 or COL2 disposed in the first unit group G1 to lower the
temperature of the wafer W to 23.degree. C. {first cooling step:
step S14-6}.
The first carrier arm 5A then receives the wafer W on the cooling
plate in the first or second cooling unit COL1 or COL2 and delivers
the wafer W onto the spin chuck 10 in the second coating unit 100B.
Thereafter, the solvent is dropped (supplied) from the solvent
supply nozzle 40 onto the front surface of the wafer W rotating
with the rotation of the spin chuck 10 as shown in FIG. 3D to
isotropically etch the coating film T as in the first embodiment
(see FIG. 2B) {etching step: step S14-7}. After the isotropic
etching with the solvent, the solvent (etching solution) is shaken
out.
After the etching treatment, the coating solution is dropped
(supplied) from the coating solution supply nozzle 30 onto the
front surface of the wafer W rotating with the rotation of the spin
chuck 10 as shown in FIG. 3E to form a substantially flat coating
film T with a small level difference h within an allowable range on
the front surface of the wafer W as in the first embodiment (see
FIG. 2C) {second coating step: step S14-8}.
After the coating film is formed as described above, the first
carrier arm 5A then receives the wafer W on the spin chuck 10 and
delivers the wafer W onto the hot plate (not shown) in the third or
fourth heating unit HP3 or HP4 disposed in the first unit group G1.
The coating film is cured (baked) as shown in FIG. 3F {second
drying step: step S14-9}.
After the curing (baking) treatment of the coating film T is
performed as described above, the first carrier arm 5A receives the
wafer W on the hot plate in the third or fourth heating unit HP3 or
HP4 and delivers the wafer W onto the cooling plate in the second
cooling unit COL2 to lower the temperature of the wafer W to
23.degree. C. {second cooling step: step S14-10}.
The first carrier arm 5A then receives the wafer W on the cooling
plate in the second cooling unit COL2 and delivers the wafer W onto
the mounting table (not shown) in the second transfer unit TRS2
(step S14-11). The pair of tweezers 4 for wafer carriage then
receives the wafer W on the mounting table in the second transfer
unit TRS2 and houses (carries) the wafer W into the cassette C on
the cassette mounting table 1a to end the processing (step
S14-12).
Note that while a case in which a flat coating film is formed on
the front surface of the wafer W with projections and depressions
through the first coating step, the first drying step, the first
cooling step, the etching step, the second coating step, the second
drying step, and the second cooling step has been described in the
above description, the second coating step and the second drying
step may be repeatedly performed in order to further decrease the
level difference in the coating film T. Alternatively, the first
coating step, the first drying step, the first cooling step, the
etching step, the second coating step, the second drying step, and
the second cooling step may be repeatedly performed a plurality of
times.
Further, when the first coating step, the first drying step, the
first cooling step, the etching step, the second coating step, the
second drying step, and the second cooling step are repeatedly
performed a plurality of times, the wafer W for which treatments
for the first time have been finished is not returned to the
cassette station 1, but the wafers W on the mounting table in the
second transfer unit TRS2 are temporarily housed in the buffer unit
700 in sequence by the first carrier arm 5A, so that after the
first treatment for the first time for the last wafer W in a lot is
finished, treatments for the second time for the wafers W
sequentially carried out of the buffer unit 700 by the first
carrier arm 5A are performed.
Besides, while a case in which the supply nozzle 40 for the solvent
being the etching solution is disposed in each of the coating units
100A and 100B so that the film forming treatment and the etching
treatment of the coating film T are performed in each of the
coating units 100A and 100B has been described in the
above-described embodiments, a dedicated etching unit comprising a
solvent supply nozzle may be separately provided to perform etching
treatment separately from the coating units 100A and 100B.
Accordingly, when such process is performed, the solvent supply
nozzle 40 may not be provided in each of the coating units 100A and
100B.
<In the Case of Etching with Hydrofluoric Acid>
First of all, in the cassette station 1, the pair of tweezers 4 for
wafer carriage accesses the cassette C housing unprocessed wafers W
on the cassette mounting table 1a and takes out one wafer W from
the cassette C (step S15-1). After taking out the wafer W from the
cassette C, the pair of tweezers 4 for wafer carriage delivers the
wafer W to the mounting table (not shown) in the first transfer
unit TRS1 disposed in the first unit group G1 on the processing
station 2 side (step S15-2). The first carrier arm 5A then receives
the wafer W from the first transfer unit TRS1 and delivers the
wafer W onto the cooling plate (not shown) in the first cooling
unit COL1 disposed in the first unit group G1 to lower the
temperature of the wafer W to 23.degree. C. {pre-treatment cooling
step: step S15-3}.
The first carrier arm 5A then receives the wafer W on the cooling
plate in the first cooling unit COL1 and delivers the wafer W onto
the spin chuck 10 in the first coating unit 100A. Thereafter, the
coating solution is dropped (supplied) from the coating solution
supply nozzle 30 onto the front surface of the wafer W rotating
with the rotation of the spin chuck 10 as shown in FIG. 3A to form
a coating film T with a level difference H on the front surface of
the wafer W as in the first embodiment (see FIG. 2A) {first coating
step: step S15-4}.
The first carrier arm 5A then receives the wafer W on the spin
chuck 10 and delivers the wafer W onto the hot plate (not shown) in
the first, second, or third heating unit HP1, HP2, or HP3 in the
first unit group G1. The wafer W is heated for a heating time
selected in advance from FIG. 5 to adjust the etching condition.
This evaporates a part of liquid in the coating film T to slightly
decrease the level difference in the coating film T {first drying
step: step S15-5}.
The first carrier arm 5A then receives the wafer W on the hot plate
in the first, second, or third heating unit HP1, HP2, or HP3 and
delivers the wafer W onto the cooling plate (not shown) in the
second cooling unit COL2 disposed in the first unit group G1 to
lower the temperature of the wafer W to 23.degree. C. {first
cooling step: step S15-6}.
The first carrier arm 5A then receives the wafer W on the cooling
plate in the second cooling unit COL2 and delivers the wafer W onto
the mounting table (not shown) in the third transfer unit TRS3
disposed in the second unit group G2. The second carrier arm 5B
then receives the wafer W on the mounting table in the third
transfer unit TRS3 and delivers the wafer W on the spin chuck 10A
in the hydrofluoric acid solution etching unit 600A. Thereafter,
the hydrofluoric acid solution is dropped (supplied) being the
etching solution from the etching solution supply nozzle 6 onto the
front surface of the wafer W rotating with the rotation of the spin
chuck 10A to isotropically etch the coating film T (see FIG. 2B)
{hydrofluoric acid solution etching step: step S15-7}. In this
event, pure water is supplied from the cleaning solution supply
nozzle 7 to suppress (stop) the etching. After the isotropic
etching with the hydrofluoric acid solution, the hydrofluoric acid
solution (etching solution) is shaken out {shaking-out drying step:
step S15-8}. In this event, the centrifugal force caused by the
rotation of the spin chuck 10A driven by the motor 12 and the wafer
W is used to remove the hydrofluoric acid solution served for the
etching, and the drying gas, for example, a N.sub.2 gas is supplied
(jetted) from the drying gas supply nozzle 8, which horizontally
scans from the position above the center of the wafer toward the
peripheral portion, onto the front surface of the wafer W to blow
the hydrofluoric acid solution served for etching to the outside to
thereby remove it.
After the etching treatment, the second carrier arm 5B receives the
wafer W on the spin chuck 10A in the hydrofluoric acid solution
etching unit 600A and delivers the wafer W onto, for example, the
mounting table (not shown) in the fourth transfer unit TRS4
disposed in the second unit group G2. The second carrier arm 5B
then receives the wafer W on the mounting table in the fourth
transfer unit TRS4 and delivers the wafer W on the cooling plate
(not shown) in the third or fourth cooling unit COL3 or COL4
disposed in the second unit group G2 to lower the temperature of
the wafer W, which will be subjected to coating treatment, to
23.degree. C. {pre-treatment cooling step: step S15-9}.
The first carrier arm 5A then receives the wafer W on the cooling
plate in the third or fourth cooling unit COL3 or COL4 and delivers
the wafer W onto the spin chuck 10 in the second coating unit 100B.
Thereafter the coating solution is dropped (supplied) from the
coating solution supply nozzle 30 onto the front surface of the
wafer W rotating with the rotation of the spin chuck 10 to form an
almost flat coating film T with a small level difference h within
an allowable range on the front surface of the wafer W (see FIG.
2C) {second coating step: step S15-10}.
After the coating film is formed as described above, the first
carrier arm 5A receives the wafer W on the spin chuck 10 and
delivers the wafer W onto the hot plate (not shown) in the fifth,
sixth, or seventh heating unit HP5, HP6, or HP7 disposed in the
second unit group G2. The coating film is then cured (baked)
{second drying step: step S15-11}.
After the curing (baking) treatment of the coating film T is
performed as described above, the first carrier arm 5A receives the
wafer W on the hot plate in the fifth, sixth, or seventh heating
unit HP5, HP6, or HP7 and delivers the wafer W onto the cooling
plate (not shown) in the second cooling unit COL2 in the first unit
group G1 to lower the temperature of the wafer W to 23.degree. C.
{second cooling step: step S15-12}.
The first carrier arm 5A then receives the wafer W on the cooling
plate in the second cooling unit COL2 and delivers the wafer W onto
the mounting table (not shown) in the second transfer unit TRS2
(step S15-13). The pair of tweezers 4 for wafer carriage then
receives the wafer on the mounting table in the second transfer
unit TRS2 and houses the wafer W into the cassette C on the
cassette mounting table 1a to end the processing (step S15-14).
While a case in which a flat coating film is formed on the front
surface of the wafer W with projections and depressions through the
first coating step, the first drying step, the first cooling step,
the hydrofluoric acid solution etching step, the second coating
step, the second drying step, and the second cooling step has been
described in the above description, the second coating step and the
second drying step may be repeatedly performed as in the above
description in order to further decrease the level difference in
the coating film T. Alternatively, the first coating step, the
first drying step, the first cooling step, the hydrofluoric acid
solution etching step, the second coating step, the second drying
step, and the second cooling step may be repeatedly performed a
plurality of times.
Further, when the first coating step, the first drying step, the
first cooling step, the hydrofluoric acid solution etching step,
the second coating step, the second drying step, and the second
cooling step are repeatedly performed a plurality of times, the
wafer W for which treatments for the first time have been finished
is not returned to the cassette station 1, but the wafers W on the
mounting table in the second transfer unit TRS2 are temporarily
housed in the buffer unit 700 in sequence by the first carrier arm
5A, so that after the treatment for the first time in the first
treatment unit, for example, the cooling unit, for the last wafer W
in a lot is finished, treatments for the second time for the wafers
W sequentially carried out of the buffer unit 700 by the first
carrier arm 5A are performed.
Note that while a case in which the etching solution is the
hydrofluoric acid solution has been described in the above
description, if an acid solution or an alkaline solution is used in
place of the hydrofluoric acid solution to perform etching
treatment, the wafer W having the coating film T formed thereon can
be carried to the acid solution etching unit 600B or the alkaline
solution etching unit 600C in place of the carriage flow to the
hydrofluoric acid solution etching unit 600A.
According to the present invention, it is also possible that when
the treatments are repeatedly performed a plurality of times, for
example, the treatments can be performed with the etching
conditions being selectively changed according to the condition of
the SOG film thickness, such that the etching for the first time is
performed using the hydrofluoric acid solution and the etching for
the second time is performed using the acid solution or the
alkaline solution, or the etching for the first time is performed
using the alkaline solution and the etching for the second time is
performed using the acid solution or the like, in addition to the
case in which the etching conditions are changed by the etching
time.
Note that while a case in which the coating solution is the SOG
solution has been described in the above embodiments, the film
formation technology according to the present invention is also
applicable to the coating solution other than the SOG solution,
such as a resist, and is also applicable to a substrate other than
the wafer W, such as an LCD substrate as a matter of course.
* * * * *